1. Field of the Invention
This invention relates to a fuel supply system for a general purpose internal combustion engine.
2. Description of the Related Art
The general purpose internal combustion engines used as prime movers in power generators, agricultural machines and various other applications have generally used a carburetor to supply fuel to the engine. In recent years, however, systems have been developed for such engines that supply fuel by means of a fuel pump and fuel injectors, i.e., by means of an FI (Fuel Injection) type fuel supply system, as, for example, disclosed in Japanese Laid-Open Patent Application No. Hei 2 (1990)-185667, particularly on page 2, lower right column, and FIG. 1.
When, as taught by the reference, the fuel pump is installed or interposed in the fuel supply pipe connecting the fuel tank with the fuel injectors, air entrainment may occur at the fuel pump if air enters and is trapped in the fuel supply pipe between the fuel tank and the fuel pump. When this happens, the fuel injectors do not inject fuel immediately, which may cause poor starting performance and other problems. Moreover, since water, foreign matter and other impurities contained in the fuel pass through the fuel pump without being removed, they are liable to cause fuel pump breakdown.